public static Progressor <T> CreateFromArray(T[] array)
{
if (array == null)
{
throw new ArgumentNullException(nameof(array));
}
var index = -1;
var proxy = new ProxyObservable <T>();
return(new Progressor <T>(proxy, (out T value) => Take(out value)));
bool Take(out T value)
{
value = default !;
public Progressor(Progressor <T> wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
var control = 0;
Predicate <T> newFilter = item => Thread.VolatileRead(ref control) == 0;
var buffer = new SafeQueue <T>();
wrapped.SubscribeAction
(
item =>
{
if (newFilter(item))
{
buffer.Add(item);
}
}
);
_proxy = new ProxyObservable <T>();
_tryTake = (out T value) =>
{
Interlocked.Increment(ref control);
try
{
if (buffer.TryTake(out value) || wrapped.TryTake(out value))
{
_proxy.OnNext(value);
return(true);
}
else
{
_done = wrapped._done;
return(false);
}
}
finally
{
Interlocked.Decrement(ref control);
}
};
}
public Progressor(TryTake <T> tryTake, Func <bool> isDone)
{
if (tryTake == null)
{
throw new ArgumentNullException("tryTake");
}
_proxy = new ProxyObservable <T>();
_tryTake = (out T value) =>
{
// This is not an overridable method, and it is not being called on the constructor.
if (tryTake(out value))
{
_proxy.OnNext(value);
return(true);
}
_done = isDone();
return(false);
};
}
public Progressor(T[] wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
var guard = 0;
var index = -1;
_proxy = new ProxyObservable <T>();
TryTake <T> tryTakeReplacement = (out T value) =>
{
value = default(T);
return(false);
};
_tryTake = (out T value) =>
{
value = default(T);
if (Thread.VolatileRead(ref guard) == 0)
{
var currentIndex = Interlocked.Increment(ref index);
if (currentIndex < wrapped.Length)
{
value = wrapped[currentIndex];
_proxy.OnNext(value);
return(true);
}
Interlocked.CompareExchange(ref guard, 1, 0);
}
if (Interlocked.CompareExchange(ref guard, 2, 1) == 1)
{
_tryTake = tryTakeReplacement;
}
return(false);
};
}
public void Close()
{
_tryTake = null;
_proxy.OnCompleted();
_proxy = null;
}
public Progressor(IEnumerable <T> preface, Progressor <T> wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
if (preface == null)
{
throw new ArgumentNullException("preface");
}
var enumerator = preface.GetEnumerator();
if (enumerator == null)
{
throw new ArgumentException("preface.GetEnumerator()");
}
var control = 0;
var guard = 0;
Predicate <T> newFilter = item => Thread.VolatileRead(ref control) == 0;
var buffer = new SafeQueue <T>();
wrapped.SubscribeAction
(
item =>
{
if (newFilter(item))
{
buffer.Add(item);
}
}
);
_proxy = new ProxyObservable <T>();
TryTake <T> tryTakeReplacement = (out T value) =>
{
Interlocked.Increment(ref control);
try
{
if (buffer.TryTake(out value) || wrapped.TryTake(out value))
{
_proxy.OnNext(value);
return(true);
}
else
{
_done = wrapped._done;
return(false);
}
}
finally
{
Interlocked.Decrement(ref control);
}
};
_tryTake = (out T value) =>
{
value = default(T);
if (Thread.VolatileRead(ref guard) == 0)
{
bool result;
// We need a lock, there is no way around it. IEnumerator is just awful. Use another overload if possible.
lock (enumerator)
{
result = enumerator.MoveNext();
if (result)
{
value = enumerator.Current;
}
}
if (result)
{
_proxy.OnNext(value);
return(true);
}
enumerator.Dispose();
Interlocked.CompareExchange(ref guard, 1, 0);
}
if (Interlocked.CompareExchange(ref guard, 2, 1) == 1)
{
_tryTake = tryTakeReplacement;
Thread.VolatileWrite(ref guard, 3);
}
else
{
ThreadingHelper.SpinWaitUntil(ref guard, 3);
}
var tryTake = _tryTake;
return(tryTake(out value));
};
}
public static Progressor <T> CreateDistinct(Progressor <T> wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
var control = 0;
SafeDictionary <T, bool> buffer = new SafeDictionary <T, bool>();
Predicate <T> newFilter = item => Thread.VolatileRead(ref control) == 0;
var proxy = new ProxyObservable <T>();
Progressor <T> result = new Progressor <T>(
(out T value) =>
{
Interlocked.Increment(ref control);
try
{
again:
foreach (KeyValuePair <T, bool> item in buffer)
{
if (!item.Value)
{
value = item.Key;
buffer.Set(value, true);
proxy.OnNext(value);
return(true);
}
}
if (wrapped.TryTake(out value))
{
bool seen;
if (!buffer.TryGetValue(value, out seen) || !seen)
{
buffer.Set(value, true);
proxy.OnNext(value);
return(true);
}
else
{
goto again;
}
}
else
{
return(false);
}
}
finally
{
Interlocked.Decrement(ref control);
}
},
proxy
);
wrapped.Subscribe
(
new CustomObserver <T>
(
() => result._done = true,
exception => result._done = true,
item =>
{
if (newFilter(item))
{
buffer.TryAdd(item, false);
}
}
)
);
return(result);
}
public static Progressor <T> CreatedFilteredConverted <TInput>(Progressor <TInput> wrapped, Predicate <TInput> filter, Converter <TInput, T> converter)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
if (filter == null)
{
throw new ArgumentNullException("filter");
}
if (converter == null)
{
throw new ArgumentNullException("converter");
}
var control = 0;
Predicate <TInput> newFilter = item => Thread.VolatileRead(ref control) == 0 && filter(item);
var buffer = new SafeQueue <T>();
var proxy = new ProxyObservable <T>();
var result = new Progressor <T>(
(out T value) =>
{
Interlocked.Increment(ref control);
try
{
TInput item;
again:
if (buffer.TryTake(out value))
{
proxy.OnNext(value);
return(true);
}
else if (wrapped.TryTake(out item))
{
if (filter(item))
{
value = converter(item);
proxy.OnNext(value);
return(true);
}
else
{
goto again;
}
}
value = default(T);
return(false);
}
finally
{
Interlocked.Decrement(ref control);
}
},
proxy
);
wrapped.Subscribe
(
new CustomObserver <TInput>
(
() => result._done = true,
exception => result._done = true,
item =>
{
if (newFilter(item))
{
buffer.Add(converter(item));
}
}
)
);
return(result);
}
private Progressor(TryTake <T> tryTake, ProxyObservable <T> proxy)
{
_proxy = proxy;
_tryTake = tryTake;
}
public Progressor(T[] preface, Progressor <T> wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
if (preface == null)
{
throw new ArgumentNullException("preface");
}
var control = 0;
var guard = 0;
var index = -1;
Predicate <T> newFilter = item => Thread.VolatileRead(ref control) == 0;
var buffer = new SafeQueue <T>();
wrapped.SubscribeAction
(
item =>
{
if (newFilter(item))
{
buffer.Add(item);
}
}
);
_proxy = new ProxyObservable <T>();
TryTake <T> tryTakeReplacement = (out T value) =>
{
Interlocked.Increment(ref control);
try
{
if (buffer.TryTake(out value) || wrapped.TryTake(out value))
{
_proxy.OnNext(value);
return(true);
}
else
{
_done = wrapped._done;
return(false);
}
}
finally
{
Interlocked.Decrement(ref control);
}
};
_tryTake = (out T value) =>
{
if (Thread.VolatileRead(ref guard) == 0)
{
var currentIndex = Interlocked.Increment(ref index);
if (currentIndex < preface.Length)
{
value = preface[currentIndex];
_proxy.OnNext(value);
return(true);
}
Interlocked.CompareExchange(ref guard, 1, 0);
}
if (Interlocked.CompareExchange(ref guard, 2, 1) == 1)
{
_tryTake = tryTakeReplacement;
Thread.VolatileWrite(ref guard, 3);
}
else
{
ThreadingHelper.SpinWaitUntil(ref guard, 3);
}
var tryTake = _tryTake;
return(tryTake(out value));
};
}
public static Progressor <T> CreateFromIObservable(IObservable <T> observable, Action exhaustedCallback = null, CancellationToken token = default)
{
if (observable == null)
{
throw new ArgumentNullException(nameof(observable));
}
if (exhaustedCallback == null)
{
exhaustedCallback = ActionHelper.GetNoopAction();
}
var buffer = new ThreadSafeQueue <T>();
var semaphore = new SemaphoreSlim(0);
var source = new CancellationTokenSource();
var subscription = observable.Subscribe
(
new CustomObserver <T>
(
source.Cancel,
_ => source.Cancel(),
OnNext
)
);
var proxy = new ProxyObservable <T>();
var tryTake = new TryTake <T>[] { null };
tryTake[0] = TakeInitial;
void OnNext(T item)
{
buffer.Add(item);
semaphore.Release();
}
bool TakeInitial(out T value)
{
if (source.IsCancellationRequested || token.IsCancellationRequested)
{
if (Interlocked.CompareExchange(ref tryTake[0], TakeReplacement, tryTake[0]) == tryTake[0])
{
Interlocked.Exchange(ref subscription, null)?.Dispose();
semaphore.Dispose();
source.Dispose();
}
}
else
{
if (exhaustedCallback != null)
{
var spinWait = new SpinWait();
while
(
semaphore.CurrentCount == 0 &&
!source.IsCancellationRequested &&
!token.IsCancellationRequested
)
{
exhaustedCallback();
spinWait.SpinOnce();
}
}
}
if (source.IsCancellationRequested || token.IsCancellationRequested)
{
return(TakeReplacement(out value));
}
try
{
semaphore.Wait(source.Token);
}
catch (OperationCanceledException exception)
{
No.Op(exception);
}
return(TakeReplacement(out value));
}
bool TakeReplacement(out T value)
{
if (buffer.TryTake(out value))
{
return(true);
}
value = default;
return(false);
}
bool Take(out T value)
{
return(tryTake[0](out value));
}
return(new Progressor <T>(proxy, Take));
}